There are increasing numbers of reported cases of infections with enterohemorrhagic Escherichia coli (EHEC), such as E. coli O-157, in recent years. Given that EHEC infection often causes life-threatening diseases such as hemorrhagic colitis, hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpra (TTP), an urgent need exists for establishing a method for the prevention and treatment of EHEC infection. EHEC produces verotoxins which are similar to Shiga toxin produced by Shigella dysenteriae, and said verotoxins are considered to be the main pathogen of the above-mentioned serious diseases.
While many antimicrobial agents having a potent antimicrobial effect against a verotoxin-producing Escherichia coli (VTEC) are known, almost all of them enhance production of verotoxins or release of them from VTEC. Those antimicrobial agents are not only useless but also harmful, because increased verotoxins often cause severe and fatal symptoms in the patients. A most preferable method for treating VTEC infections has not been established.
Meanwhile, VTEC colonizes in the intestine of livestock such as cow, pig and the like, which most likely carry and transfer VTEC to humans. Therefore, eradication of said VTEC in livestock is extremely important for the prevention of VTEC infection in humans.